The infrared thermographer uses an infrared detector and an optical imaging objective to receive the infrared radiation energy distribution pattern of the target to be measured and reflect it to a photosensitive element of the infrared detector, so as to obtain the infrared thermogram, and this kind of thermogram is corresponding to the thermal distribution field of the surface of the object. Popularly speaking, the infrared thermographer transforms the invisible infrared energy emitted by the object into a visible thermal image, and different colors in the thermal image stand for different temperatures of the object.
Generally speaking, the structure of the infrared thermographer comprises 4 parts: 1) infrared lens: receiving and focusing the infrared radiation emitted by the object to be measured; 2) infrared detector assembly: transforming the thermal radiation signal into an electrical signal; 3) electronic component: processing, analyzing and displaying the electronic component; 4) software: processing the collected temperature data and transforming it into temperature readings and images.
With respect to a visible sensor, the infrared detector owns the characteristics of low resolution, and expensiveness. Generally, the resolution of the thermographer is between 80*60 pixels and 160*120 pixels, and once the resolution of the thermographer reaches up to 640*480 pixels, there is a qualitative leap in the cost of either the infrared lens or the infrared detector assembly.
In order to enable the thermographer with low resolution to see the energy distribution of the target object clearly, various thermographer companies conduct technology improvement in the software section. Most of these technical solutions, using low-cost and high-resolution visible photosensitive sensors, conduct image enhancement for the thermal image. For example, a patented technology of American Flir (Flir) company—multi-band fusion technology (MSX), is that superimposing the counter of the visible light with the infrared image by taking advantage of the high resolution of the visible light, thus improving the definition of the low-resolution infrared image greatly. In addition, a more common technology is that blending the color of the visible light image and that of the infrared image at a certain ratio by taking advantage of the high-resolution photosensitive sensors, so as to obtain good visual effect.
Although existing technologies can conduct image enhancement for the infrared image by taking advantage of the visible light sensors, there is no substantial change for a core function of the thermographer—function of temperature measurement, since the visible light image is clear but has no direct relationship with the temperature. With respect to the point temperature measurement, the resolution is as original. Therefore, existing infrared temperature measurement technologies have problem of low resolution during temperature measurement.